// helper methods to project/unproject rays
namespace UiUtil
{
   void WindowToWorld(Vec2 pos, Vec3& orig, Vec3& dir);
   void ProjectionToWorld(Vec2 pos, Vec3& orig, Vec3& dir);
   void WorldToProjection(Vec3 pos, Vec3& projected);
   void WorldToWindow(Vec3 pos, Vec3& projected);
   void WindowToProjection(Vec3 pos, Vec3& projected);
}